The MT19937 random number engine. More...

#include <RandomLib-2010-01/RandomAlgorithm.hpp>

Public Types
enum	{ N = (P + width - 1)/width }
typedef RandomType	engine_t
typedef engine_t::type	internal_type
Static Public Member Functions
static void	Transition (long long count, internal_type statev[]) throw ()
static engine_type	Generate (engine_type y) throw ()
static void	NormalizeState (engine_type state[]) throw ()
static void	CheckState (const engine_type state[], Random_u32::type &check) throw (std::out_of_range)
static std::string	Name () throw ()
Static Public Attributes
static const unsigned	version = 0x456e4d54UL + (engine_t::width/32 - 1)
Private Types
enum	{ P = 19937, M = width == 32 ? 397 : 156, R = ((P + width - 1)/width) * width - P }
typedef engine_t::type	engine_type
Static Private Attributes
static const unsigned	width = engine_t::width
static const engine_type	mask = engine_t::mask
static const engine_type	magic
static const engine_type	upper = mask << R & mask
static const engine_type	lower = ~upper & mask

Detailed Description

The MT19937 random number engine.

This provides an interface to Mersenne Twister random number engine, MT19937. See
Makoto Matsumoto and Takuji Nishimura,
Mersenne Twister: A 623-Dimensionally Equidistributed Uniform Pseudo-Random Number Generator,
ACM TOMACS 8, 3-30 (1998)

This is adapted from the 32-bit and 64-bit C versions available at http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/MT2002/emt19937ar.html and http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/emt64.html

The template argument give the type RandomType of the "natural" result. This incorporates the bit width and the C++ type of the result. Although the two versions of MT19937 produce different sequences, the implementations here are portable across 32-bit and 64-bit architectures.

The class chiefly supplies the method for advancing the state by Transition.

Interface routines written by Charles Karney <charles@karney.com> and licensed under the LGPL. For more information, see http://randomlib.sourceforge.net/

Member Typedef Documentation

typedef RandomType RandomLib::MT19937::engine_t

The result RandomType

Definition at line 58 of file RandomAlgorithm.hpp.

typedef engine_t::type RandomLib::MT19937::internal_type

The internal numeric type for MT19337::Transition

Definition at line 62 of file RandomAlgorithm.hpp.

typedef engine_t::type RandomLib::MT19937::engine_type [private]

The unsigned type of engine_t

Definition at line 67 of file RandomAlgorithm.hpp.

Member Enumeration Documentation

anonymous enum [private]

Enumerator:

P	The Mersenne prime is 2^P - 1
M	The short lag for MT19937
R	The number of ignored bits in the first word of the state

Definition at line 72 of file RandomAlgorithm.hpp.

anonymous enum

Enumerator:

N	The size of the state. This is the long lag for MT19937.

Definition at line 107 of file RandomAlgorithm.hpp.

Member Function Documentation

void RandomLib::MT19937::Transition	(	long long	count,
		internal_type	statev[]
	)		throw () `[static]`

Advance state by count batches. For speed all N words of state are advanced together. If count is negative, the state is stepped backwards. This is the meat of the MT19937 engine.

Definition at line 689 of file Random.cpp.

References MT19937_STEP, and MT19937_REVSTEP.

static engine_type RandomLib::MT19937::Generate ( engine_type y ) throw () [static]

Manipulate a word of the state prior to output.

void RandomLib::MT19937::NormalizeState ( engine_type state[] ) throw () [static]

Convert an arbitrary state into a legal one. This consists of (a) turning on one bit if the state is all zero and (b) making 31 bits of the state consistent with the other 19937 bits.

Definition at line 716 of file Random.cpp.

void RandomLib::MT19937::CheckState	(	const engine_type	state[],
		Random_u32::type &	check
	)		throw (std::out_of_range) `[static]`

Check that the state is legal, throwing an exception if it is not. At the same time, accumulate a checksum of the state.

Definition at line 737 of file Random.cpp.

static std::string RandomLib::MT19937::Name ( ) throw () [inline, static]

Return the name of the engine

Definition at line 143 of file RandomAlgorithm.hpp.

References width.

Member Data Documentation

const unsigned RandomLib::MT19937::width = engine_t::width [static, private]

The width of the engine_t

Definition at line 71 of file RandomAlgorithm.hpp.

Referenced by Name(), and RandomLib::SFMT19937::Name().

const engine_type RandomLib::MT19937::mask = engine_t::mask [static, private]

Definition at line 86 of file RandomAlgorithm.hpp.

const engine_type RandomLib::MT19937::magic [static, private]

Initial value:

      width == 32 ? 0x9908b0dfULL : 0xb5026f5aa96619e9ULL

Magic matrix for MT19937

Definition at line 90 of file RandomAlgorithm.hpp.

const engine_type RandomLib::MT19937::upper = mask << R & mask [static, private]

Mask for top width - R bits of a word

Definition at line 95 of file RandomAlgorithm.hpp.

const engine_type RandomLib::MT19937::lower = ~upper & mask [static, private]

Mask for low R bits of a width-bit word

Definition at line 99 of file RandomAlgorithm.hpp.

const unsigned RandomLib::MT19937::version = 0x456e4d54UL + (engine_t::width/32 - 1) [static]

A version number "EnMT" or "EnMU" to ensure safety of Save/Load. This needs to be unique across RandomAlgorithms.

Definition at line 106 of file RandomAlgorithm.hpp.

The documentation for this class was generated from the following files:

Public Types

Static Public Member Functions

Static Public Attributes

Private Types

Static Private Attributes

Detailed Description

Member Typedef Documentation

Member Enumeration Documentation

Member Function Documentation

Member Data Documentation